POLR3A CRISPR/Cas9 KO Plasmid (h): sc-406851

Overview

POLR3A encodes the catalytic subunit of RNA polymerase III, a multisubunit enzyme responsible for transcription of small noncoding RNAs including tRNAs, 5S rRNA, and other Pol III products that support ribosome biogenesis and proteostasis. By coupling nutrient sensing and growth programs to the production of translation machinery components, POLR3A contributes to fundamental processes such as cell cycle progression, stress responses, and innate immune signaling linked to cytosolic nucleic acid sensing. Disruption of POLR3A function is associated with neurodevelopmental and hypomyelinating leukodystrophy phenotypes and has been used to interrogate how Pol III transcriptional output shapes cellular homeostasis. POLR3A is therefore a key node for studying transcriptional control of small RNAs, genome stability, and disease-relevant changes in cellular differentiation and metabolism.

POLR3A CRISPR/Cas9 KO Plasmid (h) is a pool of plasmids designed for targeted disruption of the POLR3A gene in human cell lines. Each plasmid in the pool co-expresses a unique sgRNA, targeting a distinct site within the POLR3A locus, alongside the Streptococcus pyogenes Cas9 nuclease, and encodes GFP to enable fluorescent identification and enrichment of successfully transfected cells. This multi-guide strategy increases the likelihood of inducing frameshifts or deletions that produce a functional knockout, offering a more robust alternative to single-guide approaches. DSBs induced at multiple sites are resolved through non-homologous end joining (NHEJ) or, when used with the included HDR donor template, homology-directed repair (HDR) at a defined target site within the locus.

When used in conjunction with the RFP-expressing HDR donor, GFP and RFP fluorescence can be used together to distinguish transfected from edited cell populations, streamlining flow cytometry-based sorting and clone selection workflows.

Homology-Directed Repair (HDR) Donor — Puromycin Cassette with RFP Reporter

For applications requiring confirmed, selectable knockout clones, POLR3A HDR Plasmid (h) includes an HDR donor construct containing a puromycin resistance cassette (PuroR) and a red fluorescent protein (RFP) reporter, flanked by homology arms specific to a defined POLR3A target site.
When co-transfected with POLR3A CRISPR/Cas9 KO Plasmid (h):

• The PuroR-RFP cassette integrates at the Cas9 cut site via HDR, disrupting the POLR3A open reading frame.
• RFP fluorescence provides an immediate visual indicator of successful integration, enabling fluorescence-based identification or sorting of edited cells prior to or alongside puromycin selection.
• Successfully edited cells are confirmed through puromycin resistance, substantially reducing clone screening burden.
• This selection strategy is ideal for generating stable, clonal KO cell lines for downstream functional studies, drug screening, or model development.

Cre-lox Cassette Removal System

The HDR donor construct features loxP sites flanking the PuroR-RFP selection cassette to allow clean marker removal following clone confirmation. Transient expression of Cre recombinase via the included Cre Vector: sc-418923 excises the cassette, leaving a minimal residual loxP site within the POLR3A locus and eliminating potential confounding effects on downstream assays.
This two-step approach:

• Minimizes disruption to local chromatin architecture and neighboring regulatory elements
• Restores a near-native genomic context at the edited locus
• Enables reuse of the puromycin selection strategy in the same cell line for additional edits

Key Features

• gRNA targeting POLR3A exon(s) critical for POLR3A function
• Co-expression of SpCas9 and sgRNA from a single plasmid for simplified delivery
• HDR donor with puromycin resistance for positive clone selection
• loxP-flanked PuroR cassette with Cre recombinase vector for seamless marker removal
• Supplied ready to use for delivery by transfection

For Research Use Only. Not Intended for Diagnostic or Therapeutic Use.